In a small bowl or larger liquid measuring cup, combine the warm water and the sugar. Sprinkle on the yeast, stir to combine, and allow to stand for 10 minutes or until frothy.
While the yeast is proofing, combine 2 tablespoons of each of the seeds in a small skillet, reserving 1 tablespoon each of sesame, flax, and sunflower seeds and ½ tablespoon of poppy seeds (you’ll use these later to top the rolls). Toast over medium heat, stirring frequently, until fragrant and the sesame seeds start to turn a light golden color.
In the bowl of a heavy-duty mixer, combine the buttermilk, melted butter, honey, and salt. Add the yeast mixture and mix well.
In another bowl, combine the whole wheat flour, vital wheat gluten, and the toasted seeds and then add to the yeast mixture and mix well. Add 2-3 cups of bread flour, ½ cup at a time, until the dough pulls away from the sides of the bowl to the center and it barely sticks to your finger when you touch it. When you reach that point, allow the mixer to knead it for 5 minutes.
While the dough is kneading, spray a large glass or metal bowl with non-stick cooking spray. When the dough is done kneading, turn the dough into the bowl and cover with a clean dish cloth. Allow it to rise in a warm place until doubled, about 1 hour.
While the dough is rising, lightly flour a work surface (or spray with non-stick cooking spray). Line 2 baking sheets with Silpat liners or parchment paper and set aside.
When the dough is done rising, transfer it to the work surface and divide it in half. Roll each half into a circle about 12″ in diameter and about ½″-½″ thick. Using a pizza wheel or a dough cutter, cut the dough into 8 equal wedges. Starting with the wide edge of each wedge, roll down to the point. Place on the prepared baking sheet and then form into a slight crescent. Repeat with remaining dough pieces. Cover and allow to rise until doubled, about 45 minutes.
When the dough has about 10 minutes left to rise, preheat oven to 375℉. Whisk together the egg white and water. Mix the reserved seeds and the oats in a small bowl. When the rolls are done rising, carefully brush the tops of each of them with the egg white mixture. Sprinkle evenly with the seeds and bake for 13-15 minutes or until golden brown on top. You can either bake them one sheet at a time (I recommend that) or rotate the sheets halfway through the baking time. Serve warm (if possible) with butter. Makes 16 rolls.